That Would Be (I think) To Turn Off Your IPad...
Press and hold down the sleep button until you see the power off slider. Slide to off and the Ipad is off. To turn back on, press and hold down the wake button (same button as 'sleep'), you'll get the Apple logo, password screen, unlock it, and then your iPad is on.
This seems to cure a lot of problems.
If you want some real time data on what your iPad is doing, go to the app store and get the 'PAD Info' app. This app tells you how much ram you are using, what version os, ip address, etc. It is ad supported but I've learned to ignore the ads. I'm sure there are other apps available.